Cooling system



COOLING SYSTEM Filed March 1'7, 1953 ZSheetS-Sheet ll A 3 /lfadfarm-'zza Sept.j22, l936. H. cAMxNaz ET AL COOLING SYSTEM Filed March17, 1933 2 Sheets-Sheet 2 MQW@ mman

Patented Sept. 22, 1936 COOLING SYSTEM narnia cammen: and Norman n.Gilman. rn-

dianapolis, Ind., assignors to General Motors Corporation, Detroit,Mich.,

Delaware Application lManch 17,

a corporation of 1933, Serial No. '661,328

climas. (cl. 12a- 113) Our invention relates to internal combustionengines designed to drive aeroplanes, vdirigible balloons and likedevices, although capable of use in any service wherein such an enginemay be 5' used; and relates particularly to and has for its objectvarious improvements in and relating to the cooling systems of suchengines wherein a liquid is circulated past to be cooled, all as willhereinafter and at length l appear.- `x The drawings accompanying andforming a part of this specication illustrate our invention yas appliedto th'e cooling of the cylinders and cylinder heads and valves of aninternaly com-f bustion engine having twelve' cylinders, arranged in twocylinder blocks of six cylinders each; the blocks being arranged at anangle of 60 degrees to one another and both being supported by asuitable crank case as is usual in V-type engines.

Our invention, however, may be used in connection with other types ofengine land is regarded as including such variations and modificationsof the particular embodiment disclosed as come withinthe scope of theconcluding claims, wherein the particular features wherein our inventionconsists are particularly pointed out and claimed.

In the drawings:

Figure 1 is a view showing a twelve cylinder V-type engine in sideelevation, the same having a cooling system in accordance with ourinvention.

Figure 2 is a. fragmentary view upon a larger scale than Figure verticaltransverse plane indicated by the line 4.-4, Figure 1; the cylindershown being one. of those of the cylinder block the nearer the observer,as will be understood.

Figure 3 is a similar view showing a section upon a plane indicated bythe line 5 5, Figure-1.

These figuresv may suggest vertically arranged cylinders, but it will beunderstood that the cylinder blocks are inclined relative to the crankcase whereby they are supported.

Figured isaviewshowingasectionupona plane at right angles to the axes ofthe cylin-v ders of the nearer block, and located near the lower limitsof the cylinder head common to all the cylinders thereof, as indicatedvby the line 8 6, Figures?l and3. A

Referring now to the drawings, the reference crankshaft,andbeiweenfortheshaftareheld; secured in the plane IZ of the which parts the theparts of the engine 1, showing a section upon a fromFigurel.

to the rear ends of the crank case sections` and which serves to supportvariousaccessorydevices involved in the operation of the engine anddriving means therefor, and parts and features associated therewith. Thefront end of the crank case has a reduction gearing housing l5 securedtoit within which is gearing whereby th speed at which the propellershaft I6 is driven is reduced to about half that of the crank shaft.

The upper part of the crank case section Il is v provided with finishedsurfaces inclined relative to one another so that the cylinder blockssup-v ported upon them will stand at an angle of degrees to one another,the surface which supports the nearer block, which appears in Figure 1,being indicated by the numeral I1.

The several cylindersof each cylinder block are enclosed within singlepiece cast aluminum alloy jackets which extend along each group and arespaced apart from the cylinders, so as to form a cooling liquid spacebetween the cylinders and the jacket, the jacket for the nearer blockbeing indicated by the numeral I8, and the cooling liquid space bythenumeral iinished upper and lower faces and the peripheral i9. Thesejackets havel wall thereof is corrugated, as shown, the ridges orcorrugations extending longitudinally of the cylinders which theyenclose; and oppositely-disposed portions 20 of this jacket wall arecurved inwardly toward oneanother, as shown'in Figu res 1 and 3, toclear a series of tie bolts 2l whereby the jacket,'the severalcylinders, and the head and other parts which make up a block are heldtogether and in place upon the inclined surfaces l1 of the upper halfofthe crank case. Each jacketL extends throughout the length of andsomewhat beyond the end cylinders of the group through whichv which itencloses and has openings the lower ends of the cylinders extend, andthe numeral 22 designates a cooling liquid conduit located 'adjacent thelower end and extending y along the outer side of, and which conduit isshown as formed integrally with the jacket wall. The

interior of this conduit communicates with the cooling liquid space I9through anmnber ofholes 23 spaced along the length thereof'and, whilethe Y jacket and other features are here referred to in the singular, itwill be appreciated that the jackets vof the two blocks are identicalwith one another, except that and because of. the conduit 22 aforesaidthey are made rights andlefts.

The cylinders of the engine, therebeing six in each block in the engineillustrated, are ened by the numeral 24. They are made from steel tubesand have upper and lower external shoulders 25, 28; and ribs 21 are alsopreferably provided between these shoulders to stiifen the wall andincrease the surface in contact with cooling the numeral 2| designatesan internally threaded clamping ring engaging said threaded part; fromwhich it follows that the jacket and cylinders, after being assembled inthe manner shown, are held together by the rings and liquid tight jointsare provided between the lower wall of the jacket and the cylinders,there being a ring for each cylinder as will be'understood. Washers 22,33 are commonly placed between the underside of the jacket and theclamping ring. and between the ring and the inclined surface I1whereupon the cylinder blocks are supported.

The hollow head 24 of each cylinder block is a single unitary casting ofaluminum alloy common to all the cylinders of the block, and hasinternal walls to isolate the combustion chambers of the cylinders fromonel another, to provide intake andexhaust passages, and other necessaryhead features; these details of head structure not being disclosed indetail as they form no part of this present invention. 'I'he lowersurface of the head rests at 36 upon the upper end of the jacket Il andthe two are secured together by stud bolts 31 extending downward fromthe head and through holes in a flange I8 at the upper end of thejacket, a suicient number of these being used to securely fasten thehead and jacket together and secure a liquid tight joint along themeeting surface at 36. The space for cooling liquid' within the headcutside thev walls which provide the combustion chambers and "passagesaforesaid extends from end to end of' the block and'provides aninternalcooling liquid passage Il along which a cooling liquid may ilow from oneend thereof "to the other to cool the headras shown in Figure 4 of thedrawings. The upper wall 4l of the head'carries pedestals 4| whereby thecam shaft and valve operating rockers not shown are supported; and theouter wall 42 thereof extends upward further than as shown in Figures 2and 3 to house the valve operating mechanism. and is closed at its opentop by a cover 43. Figure l, whereby a closed v ,chamber is provided forthe said mechanism.

Formed within the head Stand preferably located somewhat above themeeting plane 3l are annular flanges 44, one for cylinder, whichsurround the upper. extremities. of the' cylinders and'against which theshoulders 2l thereof abut;- and in assembling the parts the head isheated to expand the ilanges '44 and the'ends of the cylinders which areuppermost in the assembled block are forced into the seats provided bythese anges. Then and as the head cools the upper ends of the cylindersare grasped and compressed by the iianges and shrink Joints are formedbetween said ends and the ilanges. and the metalof, the flanges. isplaced under tension. The

Jacket Il is then put in place over the cylinders and the headand'jacketA secured together bythe bolts I1.: after which the ldwer endf the V jacket and the cylinders are fastened together; by the annularclamping rings 3l as hereinbefore explained. The assembled blocks arenext placed.t

upon tbeinclinedsurfaces I1 otthe-crank'case tightening of the nuts istransmitted to the rings and secured thereto by the tie bolts 2| as willyends of the cylinders and the head. When in use the upper ends of thecylinders and the anges ar heated and' both expand and, even though thealuminum iianges expand more per degree of `temperature rise than thesteel cylinders liquid tight joints will be maintained at such upperends because the flanges were not strained beyond their elastic limitwhen the head cooled after the assembling as aforesaid. A graspinglaction upon the cylinder ends, due to the strained condition of theanges and their tendency to contract, will therefore be maintained evenwhen the-engine is in operation and both the cylinders :nd head areheated to their operating temperaures.

The cylinder blocksvare held to the inclined surfaces I1 of the crankcase by a series of bolts 2| f bereinbefore stated, these being arrangedbetween ne cylinders and at the inwardly curved portions of the jacketas shown in Figures l, V3, and 4. 'I'he lower ends of these holdingbolts are threaded and screwed into threaded openings in the upper partof the crank case, and they extend upward through the flange 38 of the'jacket and through passages 45 in bosses 46 in the head provided bythickening the side walls thereof. Nuts 41 upon the upper ends of therods 2| act when tightened through the ilanges 44 and the upper cylindershoulders 25, and through the walls of the cylinders to force the lowercylinder shoulders 26 against the lower jacket wall, and the rings 3|against the inclined surface I1 of the crank case, thus holding theblock assembled with the crank case. As a matter of course 41 acts alsoto force the jacket I8 downward along with the cylinders but thecylinders, being made of steel, act as nonyielding struts subjected tolongitudinal compression; whereas the jacket, being corrugated asexplained, yields under compression and transmits little force to therings 3| and to the inclined surface |1 which acts as an abutmentagainst which force transmitted for the most partthrough the cylindersacts as said nuts are tightened. The cylinders being made of steel arecapable of resisting large compression forces as the nuts are tightenedwhereas the jacket, because of its corrugated construction, yields asthe nuts are tightened and transmits little force to the rings 3| andthrough them to the inclined surface I1 to which both cylinders andjacket are held by the bolts 2|. In a word, whatever force n 3| and tothe supporting surface-,I1 is transmitted substantially wholly throughthe substantially non-yieldable cylinders, because the corrugated jacketis yieldableto a degree such that no considerable force can betransmitted through it as the nuts 41 are tightened. The rods 2| arepreferably reduced in di' ameter intermediate their ends so as not tobind in the passages 4I, and their lower parts are preferablysurrounded`by tubes 4l. 'e

'Ihe rods 2| like the cylinders 24 are made ofsteel and both` have thesame or substantially the same coemcient of expansion per degree oftemvof the rods is small as compared perature rise as the engine becomesheated. but the cylinders attain a higher temperature than the rods andtherefore expand the more during the heating process. The aluminum alloyhead through which the rods extend, however, has a considerably greatercoeillcient of expansion than the cylinders and rods and expands at agreater rate than they expand; from which it follows that i the rods aresubjected to considerable strain, due to expansion of the head, as toits operating temperature. The cross section with that of the cylindersand they are reduced in diameter between their ends so as to avoidlocalization of of the jacket and the lower strain at points along theirlength due to temperature rise as the enginebecomes heated and when itis in operation.

The rods as a matter of course are not strained limit due to the heatingof always, because of their shoulders 2i against the between ltheflanges and the upper ends of the cylinders are therefore placed underincreased compression as the parts expand and are held the more firmlytogether by the elasticity of therods and their tendency to resume theircondition of initial strain due to the tightening of the nuts- I1 inassembling the engine; all of which tends betweenthe flanges and theupper ends of the cylinders when theengine is in operation. Furthermore,the corrugated construction of the jacket renders it yieldable, axially,and prevents forces due to its greater expansion (it being made ofaluminum alloy as explained) from being transmitted either to the jointsaforesaid at the upper ends of the cylinders or to the crank casethrough the clamping ring 3|, thus further contributing to the securingof permanent liquid tight joints between the upper ends of the cylindersand the head and between the lower end ends of the cylinders.

Cooling liquid which may be of any suitable kind is forced by a doubledischarge centrifugal pump 4I through two separate pipe systems, oneassociated with each cylinder block, to and through the cooling spacesof said block; from which blocks the liquid returns'to the radiatorbeyond their elastic the parts and they act resiliency, to force theflanges Il. The joints likewise of any kind,'and back to the pumpmay beused to cool the cylinders and head thedisclosed is designed especiallyfor use with a liquid which may be circulated at a system hereintemperature greatly in excess of the temperature usually present incooling systems'such, for example, as ethylene glycol, which may be usedat a temperature around 300 F. The cooling liquid, whatever itscharacteristics may be is from the pump casing through two pipes; thepipe 12 supplying the nearer cylinder block being shown in Figure 1, anda similar pipe for supplying the further block, not shown. V

The pipe 12 leads directly to the 'head 34, see Figures 1l and 4, andsuppliesa relatively large volume of cooling-liquid to the interiorthereof which flows longitudinally of said interior along the head heatsup to maintain tightness is supported from the one of said pipesdischarged the passage 3S therein and past the intake and exhaustpassages, the combustion chamber walls and like head parts, and outthrough a pipe 83 and to a radiatorand back to the pump through the pipe5l.

. Leading off from the pipe 12 is a smaller branch pipe Il whichdischarges` into the conduit 22 at the lower end of the jacket I8, andthrough which a lesser volume of liquid is suppliui to the space 'withinthe jacket I8' enclosing the cylinders. This liquid leaves the conduit22 through the several holes 23 and is thus distributed fairly uniformlyalong the lengtlof it flows upward in the space l! and through P0`rts 85leading from the upper end of said space into the cylinder head where itjoins the main volume of liquid iiowing along the head passage 35. Theports I5 as will be appreciated are located in close proximity to thejoint between the upper ends of the cylinders and the flanges Il, sothat said joint is cooled by the cooling liquid flowing throughthe-ports and past the same. By this "/rrangement a large volume ofcooling liquid is supplied to the head which is the hotter when theengine is inuse and requires the greater cooling effect, while a smallervolume is supplied to the jacket space about the cylinders which'require the cylinder block; and

less cooling. The last mentioned part is dis' tributed along the jacketspace whereby each cylinder is cooled to substantially the same ex--tent by 1streams of cooling liquid which to a considerable degree arekept separate from one another, as the liquid which enters ateachopening 23 tends to iiow upward through the jacket space l! unmixedwith liquid entering at other openings, and from the jacket space pastthe joints between the cylinders andthe head and lrough the ports 85 andinto the head passage Having thus described and explainedour inventionnwe claim and desire to secure by letters Patent:

l. In a multiple cylinder internal combustion engine, a head having aninternal longitudinally extending cooling liquid passage, and aplurality of internal annular iianges adjacent its lower end; aplurality of cylinders the upper ends of which lie within said'anges andwhich cylinders have shoulders which abut against the lower ends of saidflanges, and other shoulders adjacent their lower ends; a cooling liquidjacket enclosing all of said cylindersand spaced therefrom to provide ajacket space the upper end of which communi- Acates with the interior ofsaid head through ports arranged adjacent said flanges, so that coolingliquid ilowing therethrough will cool the. joints between the upper endsof said cylinders and said anges; a series of stud-bolts whereby theupper end of said jacket is secured to the lower end of said head;jmeansfor forcing the lower e'nd of said jacket against the shouldersaforesaid adjacent the lowerl ends of said cylinders, to thereby provideliquid tight joints between the lower end of said jacket and saidcylinders; means for supplying cooling liquid tothe lower end of saidjacket; and bolts extending from the crank case of the engine throughpassages in said head for holding said head and cylinders in place uponsaid crank case. A

2. In a multiple cylinder internal combustion engine, a head having aninternal longitudinally extending cooling liquid passage, and aplurality of annular anges adjacent its lower end; a plurality ofcylinders the upper ends of which lie within said flanges; a coolingliquid jacket en,-

closing all of said cylinders; ports whereby the interior of said jacketis placed in communication with the liquid passage in said head; boltswhereby the upper end of said jacket and the lower end of said head arefastened together; means for providing liquid tight joints between thelower end of said jacket and said cylinders; a-cooling liquid supplyconduit extending along the lower end of said jacket and communicatingwith the interior thereof at a plurality of points along said conduit; apipe through which cooling liquid is supplied to said conduit; and asecond pipe through which cooling liquid is supplied to one end of thecooling liquid passage aforesaid in said head.

3. In a multiple cylinder internal combustion engine, a plurality ofcylinders arranged in line to form a cylinder block, and a head commonto all said cylinders and having an internal cooling liquid passageextending longitudinally thereof; a cooling liquid jacket enclosing allof said cylinders and spaced therefrom to provide a cooling liquid spacethe upper end of which communicates with the passage aforesaid in saidhead; bolts for securing the upper end of said jacket to the lower, endof Said head; means for forming liquid tight joints between the lowerend of said jacket and said cylinders; a cooling liquid supply conduitformed integrally with saidl jacket and located at the lower endthereof, and which dis-.

charges into the cooling liquid space within said jacket through aplurality of holes spaced along the same; and two cooli'ngliquid supplypipes one connected with said conduitand the other with one end of thecooling liquid passage in said head` 4. In a multiple cylinder internalcombustion engine', a plurality of cylinders arranged in line to form acylinder block, and a head `common to all said cylinders and having aninternal cooling liquid passage extending longitudinally thereof;

a cooling liquid jacket enclosing all of said cylinders and spacedtherefrom to provide a cooling liquid space thev upper end of whichcommunicates with the passage aforesaid in said head; bolts for securingthe upper end of saidjacket to the lower end of said head; means forforming liquid tight joints between the lower end of said jacket and Ysaid cylinders; a cooling liquid supply conduit formed integrally withsaid jacket and located at the lower end thereof, and which dischargesinto the cooling liquid space within said jacket through a plurality ofholes spaced along the same; a'cooling liquid pump; a pipe leadingtherefrom to the rear end of the cooling liquid passage in said head; abranch pipe leading from said pipe to the rear end of the conduitaforesaid at 'the lower end of said jacket; and a pipe connected withthe front end of said head passage for returning cooling liquid to saidpump.

5. In a multiple 'cylinder internal combustion engine, a head having aninternal cooling liquid space, and a plurality of internal annular angesadjacent its lower end; a plurality of cylinders the upper ends of whichlie within said internal annular flanges, and which cylinders haveshoulders which'abut against the lower ends of said flanges, and othershoulders adjacent their lower' ends; a cooling 'liquid jacket enclosingall of said cylinders and spaced therefrom. to prolvide a jacket spacethe upper end of which communicatas with the interior of said head, andthe lower end of which jacket has holes through which the lower ends ofsaid cylinders depend, and which jacket has a flange at its upper end;.a series of stud bolts depending from said head and extend- `ingthrough holesin the flange at the upper end of said-jacket whereby theupper end of said jacket is secured to the lower end of said head;internally threaded clamping rings engaging the lower parts of saidcylinders and which rings clamp the lower end of said jacket adjacentthe holes therein against the shoulders aforesaid adjacent the lowerends ofsaid cylinders; means for supplying cooling liquid to the lowerend of said jacket; .and

bolts extending from the crank case of the engine 40 through passages insaid head forlholding said head and cylinders in place upon said crankcase.

fHARoLn cAMiNEz.

